Accession Number : ADA189030

Title :   Experimental and Analytical Investigation on a Proposed Embedded Fiber Optic Displacement Sensor.

Descriptive Note : Research and development rept.,

Corporate Author : DAVID TAYLOR RESEARCH CENTER BETHESDA MD SHIP MATERIALS ENGINEERING DEPT

Personal Author(s) : Crane, Roger ; Telegadas, Harry

PDF Url : ADA189030

Report Date : Nov 1987

Pagination or Media Count : 33

Abstract : Vibration damping measurements are currently obtained using sensors that measure beam tip displacements by determining the position of the beam cross section with time. In composites, bending-twisting couplings can occur which result in the beam undergoing two dimensional vibration motion when subjected to a bending moment. A new monitoring technique was conceptualized and validated which utilizes embedded optical fibers as the sensors. This paper discusses the experimental validation of the concept, the physics involved in the optimization of the technique, and the areas in need of further development. The experiments have shown that two dimensional vibration can be detected using this technique. Actual displacement time information was not available for the specific test apparatus used and therefore damping loss factor information was not obtained. Further development of the data acquisition system and methodology for determination of the image center is required along with an appropriate grid xy sensor in order for the technique to be acceptable as a new technique for measuring the vibration damping loss factors for materials. Keywords include: Displacement monitor; Vibration monitoring; Optical vibration sensing; Composite vibration; Damping measurement; Composite materials; and Two dimensional vibration.

Descriptors :   *BENDING MOMENTS, *COMPOSITE MATERIALS, *DETECTORS, *DISPLACEMENT, *FIBER OPTICS, *MONITORING, CROSS SECTIONS, DAMPING, DATA ACQUISITION, DETECTION, EMBEDDING, EXPERIMENTAL DATA, GRIDS, IMAGES, LOSSES, MEASUREMENT, MOTION, OPTICAL PROPERTIES, OPTIMIZATION, PHYSICS, TEST EQUIPMENT, TIME, TWO DIMENSIONAL, VALIDATION, VIBRATION

Subject Categories : Test Facilities, Equipment and Methods
      Optics
      Laminates and Composite Materials

Distribution Statement : APPROVED FOR PUBLIC RELEASE